In The Drug Book, author Michael C. Gerald details 250 milestones in the history of drugs, from the introduction of arsenic and Xanax to the passage of the 1906 Pure Food and Drug Act, the first major legislation aimed at protecting the public from dangerous medications. We asked Gerald, a professor emeritus of pharmacy at the University of Connecticut, to select a handful of the most important milestones. Read on to see what he picked.–Eds